Show all Deref implementations recursively
Fixes#87783.
This is a re-implementation of #80653, so taking the original PR comment:
This changes `rustdoc` to recursively follow `Deref` targets so that methods from all levels are added to the rendered output. This implementation displays the methods from all levels in the expanded state with separate sections for each level.

cc `@camelid`
r? `@jyn514`
It should be preferred over `def_id_no_primitives()`, so it should have
a shorter name. I also put it before `def_id_no_primitives()` so that it
shows up first in the docs.
Now that it's only implemented for `Type`, using inherent methods
instead means that imports are no longer necessary. Also, `GetDefId` is
only meant to be used with `Type`, so it shouldn't be a trait.
Move top part of print_item to Tera templates
Part of #84419.
This moves the first line of each item page (E.g. `Struct foo::Bar .... 1.0.0 [-][src]` into a Tera template.
I also moved template initialization into its own module and added a small macro to reduce duplication and opportunity for errors.
* Move call location logic from function constructor to rendering
* Fix issue with macro spans in scraping examples
* Clean up example loading logic
Documentation / newtype for DecorationInfo
Fix line number display
Serialize edition of call site, other small cleanup
Move rendering of examples into
Finalize design
Cleanup, rename found -> scraped
Softer yellow
Clean up dead code
Document scrape_examples
More simplification and documentation
Remove extra css
Test
The change to `impl Clean<Path> for hir::TraitRef<'_>` was necessary to
fix a test failure for `src/test/rustdoc/trait-alias-mention.rs`.
Here's why:
The old code path was through `impl Clean<Type> for hir::TraitRef<'_>`,
which called `resolve_type`, which in turn called `register_res`. Now,
because `PolyTrait` uses a `Path` instead of a `Type`, the impl of
`Clean<Path>` was being run, which did not call `register_res`, causing
the trait alias to not be recorded in the `external_paths` cache.
It should only ever be a `ResolvedPath`, so this (a) enforces that, and
(b) reduces the size of `Impl`.
I had to update a test because the order of the rendered auto trait impl
bounds changed. I think the order changed because rustdoc sorts auto
trait bounds using their `Debug` output.
rustdoc: Cleanup `clean` part 1
Split out from #88379.
These commits are completely independent of each other, and each is a fairly
small change (the last few are new commits; they are not from #88379):
- Remove unnecessary `Cache.*_did` fields
- rustdoc: Get symbol for `TyParam` directly
- Create a valid `Res` in `external_path()`
- Remove unused `hir_id` parameter from `resolve_type`
- Fix redundant arguments in `external_path()`
- Remove unnecessary `is_trait` argument
- rustdoc: Cleanup a pattern match in `external_generic_args()`
r? ``@jyn514``
Display associated types of implementors
Fixes#86631.
Contrary to before, it doesn't display methods. I also had to "resurrect" the `auto-hide-trait-implementations` setting. :3
Only question at this point: should I move the `render_impl` boolean arguments into one struct? We're starting to have quite a lot of them...
cc `@cynecx`
r? `@camelid`